1. Field of the Invention
The present invention relates to a technique of reducing energy consumption in a substrate processing apparatus.
2. Description of the Background Art
In the manufacturing steps of semiconductor devices, liquid crystal devices and the like, substrate processing apparatuses performing a variety of processes to semiconductor substrates and glass substrates meet the manufacturers' requirements of improving throughput by multi-unit arrangement that a plurality of process units serve one processing step, and by compounding of disposing adjacent each other process units of different types in order to continuously perform different processing steps in a single apparatus.
As such multi-unit arrangement and compounding are advanced, the power necessary for operating a substrate processing apparatus tends to increase. Especially more power is required at the time of start-up than during steady state. Therefore, one heretofore known technique of reducing the power consumption at the time of start-up is disclosed, for example, in Japanese Patent Application Laid-Open No. 10-322906.
However, when the power source of a substrate processing apparatus is turned off and thereafter turned on, in general, it takes long to stabilize the operation state of the apparatus. Therefore, in order to start processing as quickly as possible for the required time, the power source often remains turned on even when performing no processing. This is because the operation state is more likely to be stabilized than when frequently turning on and off the power source. As a result, there is no significant difference between the power consumption at low operating rates and that at high operating rates, thereby contributing to maintenance and power supply cost rises.